utils/TableGen/IntrinsicEmitter.cpp

//===- IntrinsicEmitter.cpp - Generate intrinsic information --------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file was developed by Chris Lattner and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This tablegen backend emits information about intrinsic functions.
//
//===----------------------------------------------------------------------===//

#include "IntrinsicEmitter.h"
#include "Record.h"
#include "llvm/ADT/StringExtras.h"
#include <algorithm>
using namespace llvm;

//===----------------------------------------------------------------------===//
// IntrinsicEmitter Implementation
//===----------------------------------------------------------------------===//

void IntrinsicEmitter::run(std::ostream &OS) {
  EmitSourceFileHeader("Intrinsic Function Source Fragment", OS);
  
  std::vector<CodeGenIntrinsic> Ints = LoadIntrinsics(Records);

  // Emit the enum information.
  EmitEnumInfo(Ints, OS);

  // Emit the intrinsic ID -> name table.
  EmitIntrinsicToNameTable(Ints, OS);
  
  // Emit the function name recognizer.
  EmitFnNameRecognizer(Ints, OS);
  
  // Emit the intrinsic verifier.
  EmitVerifier(Ints, OS);
  
  // Emit the intrinsic declaration generator.
  EmitGenerator(Ints, OS);
  
  // Emit mod/ref info for each function.
  EmitModRefInfo(Ints, OS);
  
  // Emit table of non-memory accessing intrinsics.
  EmitNoMemoryInfo(Ints, OS);
  
  // Emit side effect info for each intrinsic.
  EmitSideEffectInfo(Ints, OS);

  // Emit a list of intrinsics with corresponding GCC builtins.
  EmitGCCBuiltinList(Ints, OS);

  // Emit code to translate GCC builtins into LLVM intrinsics.
  EmitIntrinsicToGCCBuiltinMap(Ints, OS);
}

void IntrinsicEmitter::EmitEnumInfo(const std::vector<CodeGenIntrinsic> &Ints,
                                    std::ostream &OS) {
  OS << "// Enum values for Intrinsics.h\n";
  OS << "#ifdef GET_INTRINSIC_ENUM_VALUES\n";
  for (unsigned i = 0, e = Ints.size(); i != e; ++i) {
    OS << "    " << Ints[i].EnumName;
    OS << ((i != e-1) ? ", " : "  ");
    OS << std::string(40-Ints[i].EnumName.size(), ' ') 
      << "// " << Ints[i].Name << "\n";
  }
  OS << "#endif\n\n";
}

void IntrinsicEmitter::
EmitFnNameRecognizer(const std::vector<CodeGenIntrinsic> &Ints, 
                     std::ostream &OS) {
  // Build a function name -> intrinsic name mapping.
  std::map<std::string, unsigned> IntMapping;
  for (unsigned i = 0, e = Ints.size(); i != e; ++i)
    IntMapping[Ints[i].Name] = i;
    
  OS << "// Function name -> enum value recognizer code.\n";
  OS << "#ifdef GET_FUNCTION_RECOGNIZER\n";
  OS << "  switch (Name[5]) {\n";
  OS << "  default:\n";
  // Emit the intrinsics in sorted order.
  char LastChar = 0;
  for (std::map<std::string, unsigned>::iterator I = IntMapping.begin(),
       E = IntMapping.end(); I != E; ++I) {
    if (I->first[5] != LastChar) {
      LastChar = I->first[5];
      OS << "    break;\n";
      OS << "  case '" << LastChar << "':\n";
    }
    
    // For overloaded intrinsics, only the prefix needs to match
    if (Ints[I->second].isOverloaded)
      OS << "    if (Len >= " << I->first.size()
       << " && !memcmp(Name, \"" << I->first << "\", " << I->first.size()
       << ")) return Intrinsic::" << Ints[I->second].EnumName << ";\n";
    else 
      OS << "    if (Len == " << I->first.size()
         << " && !memcmp(Name, \"" << I->first << "\", Len)) return Intrinsic::"
         << Ints[I->second].EnumName << ";\n";
  }
  OS << "  }\n";
  OS << "#endif\n\n";
}

void IntrinsicEmitter::
EmitIntrinsicToNameTable(const std::vector<CodeGenIntrinsic> &Ints, 
                         std::ostream &OS) {
  OS << "// Intrinsic ID to name table\n";
  OS << "#ifdef GET_INTRINSIC_NAME_TABLE\n";
  OS << "  // Note that entry #0 is the invalid intrinsic!\n";
  for (unsigned i = 0, e = Ints.size(); i != e; ++i)
    OS << "  \"" << Ints[i].Name << "\",\n";
  OS << "#endif\n\n";
}

static bool EmitTypeVerify(std::ostream &OS, Record *ArgType) {
  if (ArgType->getValueAsString("TypeVal") == "...")  return true;
  
  OS << "(int)" << ArgType->getValueAsString("TypeVal") << ", ";
  // If this is an integer type, check the width is correct.
  if (ArgType->isSubClassOf("LLVMIntegerType"))
    OS << ArgType->getValueAsInt("Width") << ", ";

  // If this is a vector type, check that the subtype and size are correct.
  else if (ArgType->isSubClassOf("LLVMVectorType")) {
    EmitTypeVerify(OS, ArgType->getValueAsDef("ElTy"));
    OS << ArgType->getValueAsInt("NumElts") << ", ";
  }
  
  return false;
}

static void EmitTypeGenerate(std::ostream &OS, Record *ArgType, 
                             unsigned &ArgNo) {
  if (ArgType->isSubClassOf("LLVMIntegerType")) {
    unsigned BitWidth = ArgType->getValueAsInt("Width");
    // NOTE: The ArgNo variable here is not the absolute argument number, it is
    // the index of the "arbitrary" type in the Tys array passed to the
    // Intrinsic::getDeclaration function. Consequently, we only want to
    // increment it when we actually hit an arbitrary integer type which is
    // identified by BitWidth == 0. Getting this wrong leads to very subtle
    // bugs!
    if (BitWidth == 0)
      OS << "Tys[" << ArgNo++ << "]";
    else
      OS << "IntegerType::get(" << BitWidth << ")";
  } else if (ArgType->isSubClassOf("LLVMVectorType")) {
    OS << "VectorType::get(";
    EmitTypeGenerate(OS, ArgType->getValueAsDef("ElTy"), ArgNo);
    OS << ", " << ArgType->getValueAsInt("NumElts") << ")";
  } else if (ArgType->isSubClassOf("LLVMPointerType")) {
    OS << "PointerType::get(";
    EmitTypeGenerate(OS, ArgType->getValueAsDef("ElTy"), ArgNo);
    OS << ")";
  } else if (ArgType->isSubClassOf("LLVMEmptyStructType")) {
    OS << "StructType::get(std::vector<const Type *>())";
  } else {
    OS << "Type::getPrimitiveType(";
    OS << ArgType->getValueAsString("TypeVal") << ")";
  }
}

/// RecordListComparator - Provide a determinstic comparator for lists of
/// records.
namespace {
  struct RecordListComparator {
    bool operator()(const std::vector<Record*> &LHS,
                    const std::vector<Record*> &RHS) const {
      unsigned i = 0;
      do {
        if (i == RHS.size()) return false;  // RHS is shorter than LHS.
        if (LHS[i] != RHS[i])
          return LHS[i]->getName() < RHS[i]->getName();
      } while (++i != LHS.size());
      
      return i != RHS.size();
    }
  };
}

void IntrinsicEmitter::EmitVerifier(const std::vector<CodeGenIntrinsic> &Ints, 
                                    std::ostream &OS) {
  OS << "// Verifier::visitIntrinsicFunctionCall code.\n";
  OS << "#ifdef GET_INTRINSIC_VERIFIER\n";
  OS << "  switch (ID) {\n";
  OS << "  default: assert(0 && \"Invalid intrinsic!\");\n";
  
  // This checking can emit a lot of very common code.  To reduce the amount of
  // code that we emit, batch up cases that have identical types.  This avoids
  // problems where GCC can run out of memory compiling Verifier.cpp.
  typedef std::map<std::vector<Record*>, std::vector<unsigned>, 
    RecordListComparator> MapTy;
  MapTy UniqueArgInfos;
  
  // Compute the unique argument type info.
  for (unsigned i = 0, e = Ints.size(); i != e; ++i)
    UniqueArgInfos[Ints[i].ArgTypeDefs].push_back(i);

  // Loop through the array, emitting one comparison for each batch.
  for (MapTy::iterator I = UniqueArgInfos.begin(),
       E = UniqueArgInfos.end(); I != E; ++I) {
    for (unsigned i = 0, e = I->second.size(); i != e; ++i) {
      OS << "  case Intrinsic::" << Ints[I->second[i]].EnumName << ":\t\t// "
         << Ints[I->second[i]].Name << "\n";
    }
    
    const std::vector<Record*> &ArgTypes = I->first;
    OS << "    VerifyIntrinsicPrototype(ID, IF, ";
    bool VarArg = false;
    for (unsigned j = 0; j != ArgTypes.size(); ++j) {
      VarArg = EmitTypeVerify(OS, ArgTypes[j]);
      if (VarArg) {
        if ((j+1) != ArgTypes.size())
          throw "Var arg type not last argument";
        break;
      }
    }
      
    OS << (VarArg ? "-2);\n" : "-1);\n");
    OS << "    break;\n";
  }
  OS << "  }\n";
  OS << "#endif\n\n";
}

void IntrinsicEmitter::EmitGenerator(const std::vector<CodeGenIntrinsic> &Ints, 
                                     std::ostream &OS) {
  OS << "// Code for generating Intrinsic function declarations.\n";
  OS << "#ifdef GET_INTRINSIC_GENERATOR\n";
  OS << "  switch (id) {\n";
  OS << "  default: assert(0 && \"Invalid intrinsic!\");\n";
  
  // Similar to GET_INTRINSIC_VERIFIER, batch up cases that have identical
  // types.
  typedef std::map<std::vector<Record*>, std::vector<unsigned>, 
    RecordListComparator> MapTy;
  MapTy UniqueArgInfos;
  
  // Compute the unique argument type info.
  for (unsigned i = 0, e = Ints.size(); i != e; ++i)
    UniqueArgInfos[Ints[i].ArgTypeDefs].push_back(i);

  // Loop through the array, emitting one generator for each batch.
  for (MapTy::iterator I = UniqueArgInfos.begin(),
       E = UniqueArgInfos.end(); I != E; ++I) {
    for (unsigned i = 0, e = I->second.size(); i != e; ++i) {
      OS << "  case Intrinsic::" << Ints[I->second[i]].EnumName << ":\t\t// "
         << Ints[I->second[i]].Name << "\n";
    }
    
    const std::vector<Record*> &ArgTypes = I->first;
    unsigned N = ArgTypes.size();

    if (ArgTypes[N-1]->getValueAsString("TypeVal") == "...") {
      OS << "    IsVarArg = true;\n";
      --N;
    }
    
    unsigned ArgNo = 0;
    OS << "    ResultTy = ";
    EmitTypeGenerate(OS, ArgTypes[0], ArgNo);
    OS << ";\n";
    
    for (unsigned j = 1; j != N; ++j) {
      OS << "    ArgTys.push_back(";
      EmitTypeGenerate(OS, ArgTypes[j], ArgNo);
      OS << ");\n";
    }
    OS << "    break;\n";
  }
  OS << "  }\n";
  OS << "#endif\n\n";
}

void IntrinsicEmitter::EmitModRefInfo(const std::vector<CodeGenIntrinsic> &Ints,
                                      std::ostream &OS) {
  OS << "// BasicAliasAnalysis code.\n";
  OS << "#ifdef GET_MODREF_BEHAVIOR\n";
  for (unsigned i = 0, e = Ints.size(); i != e; ++i) {
    switch (Ints[i].ModRef) {
    default: break;
    case CodeGenIntrinsic::NoMem:
      OS << "  NoMemoryTable->push_back(\"" << Ints[i].Name << "\");\n";
      break;
    case CodeGenIntrinsic::ReadArgMem:
    case CodeGenIntrinsic::ReadMem:
      OS << "  OnlyReadsMemoryTable->push_back(\"" << Ints[i].Name << "\");\n";
      break;
    }
  }
  OS << "#endif\n\n";
}

void IntrinsicEmitter::
EmitNoMemoryInfo(const std::vector<CodeGenIntrinsic> &Ints, std::ostream &OS) {
  OS << "// SelectionDAGIsel code.\n";
  OS << "#ifdef GET_NO_MEMORY_INTRINSICS\n";
  OS << "  switch (IntrinsicID) {\n";
  OS << "  default: break;\n";
  for (unsigned i = 0, e = Ints.size(); i != e; ++i) {
    switch (Ints[i].ModRef) {
    default: break;
    case CodeGenIntrinsic::NoMem:
      OS << "  case Intrinsic::" << Ints[i].EnumName << ":\n";
      break;
    }
  }
  OS << "    return true; // These intrinsics have no side effects.\n";
  OS << "  }\n";
  OS << "#endif\n\n";
}

void IntrinsicEmitter::
EmitSideEffectInfo(const std::vector<CodeGenIntrinsic> &Ints, std::ostream &OS){
  OS << "// Return true if doesn't access or only reads memory.\n";
  OS << "#ifdef GET_SIDE_EFFECT_INFO\n";
  OS << "  switch (IntrinsicID) {\n";
  OS << "  default: break;\n";
  for (unsigned i = 0, e = Ints.size(); i != e; ++i) {
    switch (Ints[i].ModRef) {
    default: break;
    case CodeGenIntrinsic::NoMem:
    case CodeGenIntrinsic::ReadArgMem:
    case CodeGenIntrinsic::ReadMem:
      OS << "  case Intrinsic::" << Ints[i].EnumName << ":\n";
      break;
    }
  }
  OS << "    return true; // These intrinsics have no side effects.\n";
  OS << "  }\n";
  OS << "#endif\n\n";
}

void IntrinsicEmitter::
EmitGCCBuiltinList(const std::vector<CodeGenIntrinsic> &Ints, std::ostream &OS){
  OS << "// Get the GCC builtin that corresponds to an LLVM intrinsic.\n";
  OS << "#ifdef GET_GCC_BUILTIN_NAME\n";
  OS << "  switch (F->getIntrinsicID()) {\n";
  OS << "  default: BuiltinName = \"\"; break;\n";
  for (unsigned i = 0, e = Ints.size(); i != e; ++i) {
    if (!Ints[i].GCCBuiltinName.empty()) {
      OS << "  case Intrinsic::" << Ints[i].EnumName << ": BuiltinName = \""
         << Ints[i].GCCBuiltinName << "\"; break;\n";
    }
  }
  OS << "  }\n";
  OS << "#endif\n\n";
}

void IntrinsicEmitter::
EmitIntrinsicToGCCBuiltinMap(const std::vector<CodeGenIntrinsic> &Ints, 
                             std::ostream &OS) {
  typedef std::map<std::pair<std::string, std::string>, std::string> BIMTy;
  BIMTy BuiltinMap;
  for (unsigned i = 0, e = Ints.size(); i != e; ++i) {
    if (!Ints[i].GCCBuiltinName.empty()) {
      std::pair<std::string, std::string> Key(Ints[i].GCCBuiltinName,
                                              Ints[i].TargetPrefix);
      if (!BuiltinMap.insert(std::make_pair(Key, Ints[i].EnumName)).second)
        throw "Intrinsic '" + Ints[i].TheDef->getName() +
              "': duplicate GCC builtin name!";
    }
  }
  
  OS << "// Get the LLVM intrinsic that corresponds to a GCC builtin.\n";
  OS << "// This is used by the C front-end.  The GCC builtin name is passed\n";
  OS << "// in as BuiltinName, and a target prefix (e.g. 'ppc') is passed\n";
  OS << "// in as TargetPrefix.  The result is assigned to 'IntrinsicID'.\n";
  OS << "#ifdef GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN\n";
  OS << "  if (0);\n";
  // Note: this could emit significantly better code if we cared.
  for (BIMTy::iterator I = BuiltinMap.begin(), E = BuiltinMap.end();I != E;++I){
    OS << "  else if (";
    if (!I->first.second.empty()) {
      // Emit this as a strcmp, so it can be constant folded by the FE.
      OS << "!strcmp(TargetPrefix, \"" << I->first.second << "\") &&\n"
         << "           ";
    }
    OS << "!strcmp(BuiltinName, \"" << I->first.first << "\"))\n";
    OS << "    IntrinsicID = Intrinsic::" << I->second << ";\n";
  }
  OS << "  else\n";
  OS << "    IntrinsicID = Intrinsic::not_intrinsic;\n";
  OS << "#endif\n\n";
}